Genetic diversity and natural selection

Question 1

define genetic diversity

Answer 1

differences in DNA/base sequence/ alleles

in a gene pool

Question 2

define natural selection

Answer 2

individuals with particular characteristic have greater chance of survival than without
so more likely to breed + pass on these characteristics
these characteristics increase in frequency over generations

Question 3

define population

Answer 3

group of interbreeding individuals of the same species

Question 4

define gene pool

Answer 4

collection of different genes within interbreeding populations

Question 5

define alleles

Answer 5

different versions of the same genes

Question 6

define allele frequency

Answer 6

how often a particular allele occurs within a population

Question 7

what’s the link between natural selection and evolution

Answer 7

natural selection = -central mechanisms of evolutionary change
- process responsible for evolution of adaptive features

Question 8

what is natural selection

Answer 8

a process

which leads to evolution

Question 9

what is evolution

Answer 9

change in allele frequency

over many generations in a population

Question 10

what types of adaptations are there

Answer 10

anatomical
physiological
behavioural

Question 11

what is the process of natural selection

Answer 11

new alleles by random mutations
if new allele increase chance of survival in environment = more likely to survive + reproduce
reproduction= passes on advantageous allele to next generation

Question 12

define selective pressure

Answer 12

causes natural selection e.g antibiotic resistance

Question 13

what are the two types of natural selection

Answer 13

selective

directional

Question 14

what is directional selection

Answer 14

one of the extremes has selective advantage
occurs when change in environment
modal trait changes

Question 15

what is stabilising selection

Answer 15

modal trait has advantage
occurs when no change in environment
modal trait remains the same
standard deviation decreases as individuals with extreme trait decreases

Question 16

how does genetic diversity occur

Answer 16

mutation: deletion, addition, substitution, nucleotide
deletion/ translocation of chromosomes
aneuploidy, polyploidy

meiosis: independent segregation
random fertilisation
crossing over

Question 17

how can genetic diversity be increased

Answer 17

crossing over
independent segregation
genetic mutations
outbreeding 
immigration

Question 18

what is the importance of genetic diversity

Answer 18

greater genetic diversity = species more likely to adapt to changes in environment
because wider range of alleles so wider range of characteristics

Question 19

anatomical adaptations are

Answer 19

structural features e.g bright coloured feather

Question 20

physiological adaptations are

Answer 20

processes inside the body /e.g hibernation

Question 21

behavioural adaptations are

Answer 21

the way an organism acts e.g birds with elaborate mating rituals

Question 22

what is the process of natural selection for evolution of populations

Answer 22

• variations of alleles in population, due to random DNA mutations
• selection pressure/change in environment
• advantageous allele = increased chance of survival + reproduction = reproductive success
• advantageous allele passed onto offspring
• frequency of advantageous allele + characteristic increases in population
• over many generations

Question 23

what is artificial selection

Answer 23

when humans decide what members to breed

Question 24

what does artificial selection do

Answer 24

allows desirable alleles to be maintained

Question 25

what can artificial selection lead to

Answer 25

interbreeding

Question 26

interbreeding can reduce…

Answer 26

genetic diversity

Question 27

what else can interbreeding lead to

Answer 27

increased risk of disease in whole population

Question 28

what can we infer if standard deviations overlap

Answer 28

not a great significance in values